Notch2 Expressed by Myofibers Influences Muscle Mass and Fiber Types

Notch receptors play crucial roles in the cell-fate decisions of tissue stem cells during development and regeneration. Notch1-3 receptors are expressed by satellite cells and their progeny. Here we found that Notch2, but not Notch1 or Notch3, was expressed in fully differentiated myofibers. Using transgenic mice that expressed a muscle-specific active form of Notch2 (N2ICD-mTG), we found that Notch2 activation remarkably reduced muscle mass and strength with a shift toward slow fibers. Transcriptome analyses revealed that growth differentiation factor 11 (GDF11) was highly up-regulated in muscles of N2ICD-mTG mice, and crucially, N2ICD-induced muscle atrophy was rescued by siRNA-mediated reduction of GDF11 expression. These data suggest that Notch2 functions in muscle to regulate muscle mass, in part, through induction of GDF11 expression, and reveal a novel aspect of Notch signaling in a terminally differentiated adult tissue. Activated Notch2 (N2ICD)-induced gene expression in mouse muscle tissues was measured. A single experiment was performed.